Condensed Consolidated Statements Of Stockholders' Equity And Comprehensive Income (USD $) In Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Comprehensive Income (loss) [Member]	Total
Balance at Dec. 31, 2010	$ 240	$ 113,412	$ 188,894	$ 151		$ 302,697
Balance, shares at Dec. 31, 2010	24,011
Net income			43,824		43,824	43,824
Other comprehensive gain:
Unrealized loss on cash flow hedge, net of tax				(1,275)	(1,275)	(1,275)
Exercise of stock options and issuance of share-based awards, net of shares withheld for employee taxes, shares	461
Exercise of stock options and issuance of share-based awards, net of shares withheld for employee taxes	5	(2,193)				(2,188)
Stock-based compensation		5,980				5,980
Tax benefit related to stock-based compensation		4,883				4,883
Balance at Sep. 30, 2011	$ 245	$ 122,082	$ 232,718	$ (1,124)	$ 42,549	$ 353,921
Balance, shares at Sep. 30, 2011	24,472